EXPERIMENTAL THERAPY OF SPINAL CORD INJURY

脊髓损伤的实验治疗

• 批准号: 6243841
• 负责人: WISE YOUNG
• 金额: $ 19万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-20 至 1998-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6243841
• 关键词: FK506; calcineurin; combination chemotherapy; cyclosporines; disease /disorder model; gender difference; immunocytochemistry; laboratory rat; methylprednisolone; nervous system disorder chemotherapy; neuropharmacology; neuroprotectants; nonhuman therapy evaluation; pharmacokinetics; sirolimus; spinal cord injury

We recently discovered the cyclosporin A (CsA), a commonly used immunosuppressant, is neuroprotective in a rat model of spinal cord injury (SCI), CsA inhibitors calcineurin, a key intracellular phosphatase in neurons and lymphocyts. Recent studies have shown that calcineurin induces and regulates immune and inflammatory responses of cells, as well as calcium channels, neurotransmitter receptors, and secretion. We consequently propose to study CsA and other calcineurin inhibitors further. Our first aim is to determine whether calcineurin inhibition protects the spinal cord. We will compare the effects of methylprednisolone (MP, the current standard therapy for human SCI), CsA, CsA+MP, FK506, rapamuycin, and FK506+rapamycin. FK506 is a macrolide antibiotic which inhibits calcineurin but by binding to a different protein. Rapamycin is a macrolide that does not inhibit calcineurin and antagonizes FK506 inhibition of calcineurin. If Cs
and FK506 are neuroprotective, rapamycin is not and antagonizes FK506's neuroprotective effect, the data would argue strongly that calcineurin plays a major role in SCI. Our second aim is to establish that GsA and FK506 improves motor recovery and saves axons in the spinal cord. We will assess locomotor recovery, count spinal axons, and assess myelination in the rats at 6 weeks after injury and CsA, MP, CsA+MP, FK506, and FK506+ rapamycin treatment. Our third aim is to study the effects of calcineurin inhibitors on blood flow in injured spinal cords. Calcineurin stimulates the nitric oxide synthase which produces nitric oxide, a potent vasodilating agent. We propose the nitric oxide causes an initial increase in flow and delays onset of blood flow loss in SCI. Our fourth aim is to determine whether serotonin (5-HT) and gamma-amino- butyrate acid (GABA) contribute to SCI. Both neurotransmitters are released in injured spinal cords. We recently found that spinal axons have 5-HT and GABA receptors. Calcineurin prevents desensitization of 5-HT gated calcium channels and CsA may protect spinal axons by turning off 5-HT receptors. Mianserin, a 5-HT receptor blocker, has been reported to be neuroprotective in SCI. We will therefore assess the effects of calcineurin on 5-HT and GABA-induced excitability changes in vitro and in vivo. Our fifth aim is to assess the role of glutamate in spinal cord injury. Glutamate is known to injure neurons and glutamate receptor blockers have been reported to be neuroprotective in spinal cord injury. Recent studies, however, report that calcineurin inactivates glutamate channels and also enhances glutamate release. Calcineurin inhibitors therefore may paradoxically enhance glutamate-induced neurotoxicity in SCI. To resolve this issue, we will examine glutamate sensitivity in spinal cords and determine the effects of calcincurin inhibitors on glutamate-mediated axonal changes, in vitro and in vivo.

我们最近发现了Cyclosporin A（CSA），这是一种常用的 免疫抑制剂，在脊髓损伤的大鼠模型中具有神经保护作用 （SCI），CSA抑制剂钙调神经蛋白，一种关键的细胞内磷酸酶 神经元和淋巴细胞。 最近的研究表明，钙调神经酶诱导 并调节细胞的免疫和炎症反应，以及 钙通道，神经递质受体和分泌。 我们 因此，建议进一步研究CSA和其他钙调蛋白抑制剂。 我们的第一个目的是确定钙调神经酶抑制是否保护 脊髓。 我们将比较甲基强酮的影响（MP， 人类科学），CSA，CSA+MP，FK506，Rapamuycin的当前标准疗法， 和FK506+雷帕霉素。 FK506是一种抑制的大环内酯类抗生素 钙调神经酶，但通过与不同的蛋白质结合。 雷帕霉素是 不抑制钙调神经蛋白并拮抗FK506的大花环 抑制钙调蛋白。 如果CS和FK506是神经保护性的， 雷帕霉素不是，并且拮抗FK506的神经保护作用，数据 会强烈认为钙调神经酶在SCI中起着重要作用。 我们的第二个目的是确定GSA和FK506改善了运动恢复 并将轴突保存在脊髓中。 我们将评估运动恢复， 计算脊柱轴突，并在6周后评估大鼠的髓鞘化 受伤和CSA，MP，CSA+ MP，FK506和FK506+雷帕霉素治疗。 我们的第三个目的是研究钙调神经酶抑制剂对血液的影响 受伤的脊髓流动。 钙调蛋白刺激一氧化氮 合成酶产生一氧化氮，这是一种有效的血管扩张剂。 我们 提出一氧化氮会导致流量和延迟的初始增加 SCI血液流失的发作。 我们的第四个目的是确定5-羟色胺（5-HT）和γ-氨基 - 丁酸酯酸（GABA）有助于SCI。 两个神经递质都是 在受伤的脊髓中释放。 我们最近发现脊柱轴突有 5-HT和GABA受体。 钙调神经酶防止5-HT脱敏 封闭的钙通道和CSA可以通过关闭5-HT保护脊柱轴突 受体。 据报道，5-HT受体阻滞剂Mianserin是 Sci中的神经保护作用。 因此，我们将评估 5-HT和GABA诱导的兴奋性在体外和IN的兴奋性变化 体内。 我们的第五个目标是评估谷氨酸在脊髓损伤中的作用。 已知谷氨酸会损害神经元，谷氨酸受体阻滞剂具有 据报道在脊髓损伤方面具有神经保护作用。 最近的研究， 但是，报告钙调神经蛋白会使谷氨酸通道失活，也使 增强谷氨酸释放。 因此，钙调蛋白抑制剂可能 矛盾地增强了谷氨酸诱导的SCI中的神经毒性。 解决 这个问题，我们将检查脊髓中的谷氨酸敏感性 确定钙蛋白酶抑制剂对谷氨酸介导的影响 轴突变化，体外和体内。